“Little bit you speak Farsi?” my two-year-old daughter Yara asked me yesterday.

My wife and I are raising Yara and her little sister in a bilingual household with both Farsi (Persian) and English. Although I’m the English-speaker 99 percent of the time, I have indeed been making an effort to learn Farsi. As a historian, I find it an especially fun language because there are so many hints of past events embedded in the vocabulary itself.

A favorite example: there is a century-old debate among historical linguists that hinges on the Farsi word div , which describes a type of demon from Persian mythology (you can see two examples below). Farsi is an Indo-European language, and div is easily traceable back to an ancient Indo-European word for gods or divinities. The original word, used by proto-Indo-European speakers who lived around 5000 BCE, sounded something like deywós and likely referred to a sun god .…